Method And Device For Updating A Target Altitude For An Emergency Descent Of An Aircraft

• US 20120022725A1
• Filed: 07/15/2011
• Published: 01/26/2012
• Est. Priority Date: 07/20/2010
• Status: Active Grant

• Current Assignee: Airbus Operations (European Aeronautic Defence and Space Company EADS NV)
• Original Assignee: Airbus Operations (European Aeronautic Defence and Space Company EADS NV)
• Inventors: Botargues, Paule, Grandperret, Erwin, Burel, Lucas, Bourret, Thierry
• Granted Patent: US 8,725,322 B2
• Time in Patent Office: Days
• US Class Current: 701/10
• CPC Class Codes: G01C 5/005 altimeters for aircraft G01C5/02, G01C5/06 take precedence
• CPC Class Codes: G05D 1/0055 with safety arrangements
• CPC Class Codes: G05D 1/0688 Emergency descent

Abstract

Method and device for updating a target altitude for an emergency descent of an aircraft.

The device (1) comprises means (2, 3, 4, 7) for determining an updated target altitude which takes into account variations of barometric pressure and which is able to replace a target altitude that must be reached at the end of the emergency descent.

Claims

1. A method for updating a target altitude intended for an emergency descent of an aircraft (AC), this target altitude representing the altitude to be reached by the aircraft at the end of the emergency descent, a method wherein:

a) a target security altitude is determined as a function of the emergency descent, by automatically and repeatedly carrying out the following operations, from the activation of the emergency descent, and on a reference horizontal distance ahead of the aircraft (AC) with respect to an initial position of said aircraft (AC) upon the activation of the emergency descent;

a remaining horizontal distance is determined, representing a horizontal distance remaining to be covered by the aircraft (AC) from its current position until a position located at said reference horizontal distance ahead of said initial position;

a security altitude is determined being representative of said remaining horizontal distance;

this security altitude is compared to a threshold altitude; and

as the target security altitude, the highest value is selected between said security altitude and said threshold altitude;

b) a correction value is determined taking into account variations of barometric pressure occurring upon the emergency descent; and

c) the sum of said target security altitude and said correction value is calculated for obtaining an updated target altitude being able to replace the target altitude to be reached before the end of the emergency descent.

2. The method according to claim 1, characterized in that at step b), for determining the correction value:

the lowest atmospheric pressure and the highest atmospheric pressure encountered this day are taken into account;

first and second differences are determined between a barometric reference and, respectively, said lowest atmospheric pressure and said highest atmospheric pressure; and

the highest difference is converted in absolute value, between these first and second differences, into a height value representing said correction value.

3. The method according to claim 1, characterized in that at step b), for determining the correction value, the following operations are automatically and repeatedly carried out:

the current barometric altitude of the aircraft (AC) is determined;

the current height of the aircraft (AC) is determined with respect to the level of the sea, through means other than barometric measurement means; and

said current height is subtracted from said current barometric altitude so as to obtain said correction value.

4. The method according to claim 1, characterized in that at step c), the target altitude is replaced with the updated target altitude, repeatedly upon each determination of a new updated target altitude.

5. The method according to claim 1, characterized in that at step c), the target altitude is replaced with the updated target altitude, only if the updated target altitude is higher than said target altitude.

6. The method according to claim 1, said updated target altitude and the target altitude being repeatedly calculated by calculation pitches, characterized in that at step c):

the difference is calculated between the target altitude for a pitch N−

1, N being an integer, and the updated target altitude for a pitch N;

the absolute value of this difference is compared with respect to a threshold value; and

the target altitude is replaced for a pitch N by the updated target altitude for this pitch N, only if the absolute value of said difference is higher than or equal to said threshold value.

7. A process for automatically controlling an emergency descent of an aircraft, a process wherein the following successive operations are carried out:

a) a set of vertical setpoints is automatically determined, comprising;

a target altitude representing an altitude to be reached by the aircraft at the end of the emergency descent; and

a target speed representing a speed that the aircraft (AC) should respect upon the emergency descent;

b) a set of lateral setpoints is automatically determined, representing a lateral maneuver to be carried out upon the emergency descent; and

c) the aircraft (AC) is automatically guided so that it simultaneously respects said set of vertical setpoints and said set of lateral setpoints until reaching said target altitude.

characterized in that at step a), said target altitude is updated implementing the method specified in claim 1.

8. A device for updating a target altitude intended for an emergency descent of an aircraft (AC), this target altitude representing the altitude to be reached by the aircraft at the end of the emergency descent, said device (1) comprising:

means (2) for determining a target security altitude as a function of the emergency descent, automatically and repeatedly carrying it out, from the activation of the emergency descent, and on a reference horizontal distance ahead of the aircraft (AC) with respect to an initial position of said aircraft (AC) upon the activation of the emergency descent, comprising elements;

for determining a remaining horizontal distance, representing a horizontal distance remaining to be covered by the aircraft (AC) from its current position until a position located at said reference horizontal distance ahead of said initial position;

for determining a security altitude being representative of said remaining horizontal distance;

for comparing this security altitude to a threshold altitude; and

for selecting, as a target security altitude, the highest value between said security altitude and said threshold altitude;

means (3) for determining a correction value taking into account variations of barometric pressure occurring upon the emergency descent; and

means (4) for calculating the sum of said target security altitude and said correction value for obtaining an updated target altitude being able to replace a target altitude to be reached at the end of the emergency descent.

9. A system for automatically controlling an emergency descent of an aircraft, comprising:

first means (22) for automatically determining a set of vertical setpoints comprising;

a target altitude representing an altitude to be reached by the aircraft at the end of the emergency descent; and

a target speed representing a speed that the aircraft should respect upon the emergency descent;

second means (22) for automatically determining a set of lateral setpoints, representing a lateral maneuver to be carried out upon the emergency descent; and

third means (24) for automatically guiding the aircraft (AC) so that it simultaneously respects said set of vertical setpoints and said set of lateral setpoints until reaching said target altitude, characterized in that said first means (22) comprise the device (1) as specified in claim 8 for updating said target altitude.